lo March, 1910.] The Oniou Kcl-ivonn. 169 



eel-worm. Before this seed was sown, a quantity was tested by placing 

 it on moist blotting paper, and allowing it to germinate. On microscopical 

 examination ol the young plants, no nematodes were found. Some of this 

 sterilized soil was placed in a Petri dish, moistened, and strips of onion 

 laid on its surface. No worms were found in any of the strips. This 

 method of obtaining a pure seed bed by steam sterilization is frequently 

 used by nurserymen, a special plant for the purpose being erected for 

 the treatment of a large quantity of soil at one time. 



As showing the immense importance of the scientific study of nema- 

 todes to the farmer and horticulturist generally, the Bureau of Plant 

 Industry of the United States established a Station at Miami, Florida, 

 some years ago, under the charge of Dr. Bessey, for the sole purpose of 

 investigating and collecting information regarding the life history, habits, 

 and the ravages caused by the various forms of eel-worm on plant life. 

 For it is known and recorded that not only are onions attacked by nema- 

 todes, but the allied species of this family may be found attacking vines, 

 peaches, figs, oranges, lemons, cotton, potatoes, tomatoes, beet, cabbage, 

 parsnips, lettuce, melon, maize, coffee, sugar cane, bananas, tobacco, clover, 

 peas, oats, barley, most bulbs, and many of the grasses. Various kinds 

 ■of weeds are also attacked. Lavergne found, in Chili, that the roots of the 

 bitter orange were resistant, and by grafting the sweet orange on a bitter 

 stock, succeeded in producing a plant immune from its ravages. Accord- 

 ing to the United States Y ear-Book of Agriculture, 1907, a tobacco plant 

 possessing resistant qualities has been produced. 



Sugar Beet as a Catch Crop. 



Sugar beet suffers severely from the presence of eel-worm on the Con- 

 tinent of Europe (Massee), and in the event of the much-discussed project 

 •of sugar-beet cultivation bemg again realized in this State, a sharp 

 look out should be kept for the appearance of eel-worm disease, which is 

 recognised by yellowing and wilting of the foliage, and by the presence 

 of small knots or galls on the root fibres, which are produced in excess in 

 -such cases. Sugar beet having been suggested bv certain observers as a 

 means of freeing the land from nematodes, special attention is directed 

 To the foregoing. 



Rotation of Crops. 



The destruction caused by eel -worms is much more serious where there 

 is no rotation of crops, as it is seen tO' a much greater extent where the 

 .so-called intensive cultivation is practised, or where the same crop is grown 

 year after yeax. In fact, the horticulturist is suffering to a much greater 

 extent than the farmer, simply because he ignores the fundamental agri- 

 cultural law, rotation of crops. Eel-worms, in common with other animals, 

 are to a certain extent restricted in their choice of food, and if a crop of 

 oats, say, is attacked and the soil consequently infected, the eel-worms 

 usually perish for lack of food before oats are again sown on the same 

 land. 



If an examination be made of onion plants growing on infected land, 

 manv will be found showing a peculiar stunted and distorted appearance, 

 well seen in the photograph on page 164. If a small piece of these 

 •stunted onion plants be taken, placed in water in a watchglass, teased out 

 and examined under a low-power microscope, immense numbers of worms 

 and eggs will be seen, the worms wriggling to and fro in the fluid. 



